【摘要】 寻找地震前兆是国内外地震预报的难点.在实验室开展岩石变形实验,观测相关物理量的演化特征和规律,是前兆探索中重要的基础工作.本文对压性雁列断层进行变形实验,根据应力时间曲线将具有前兆意义的变形阶段分为强偏离线性阶段、亚失稳阶段和失稳阶段,利用红外热像仪记录各个阶段的热场变化,特别是亚失稳阶段的热场表现.研究结果显示:强偏离线性阶段,岩桥区挤压升温;亚失稳阶段,断层带增温,且高温点扩展连通,断层带内侧卸载降温,断层带上的协同化增温和断层带内侧(包含岩桥区)的协同化降温是失稳前的重要信号;失稳阶段,应力释放,标本整体降温,只有断层带因摩擦升温.总之,亚失稳阶段的热场具有明显特征,利于识别出亚失稳态;不同变形阶段、不同构造部位温度变化不同,在寻找与构造活动相关的热异常时,应考虑变形所处的阶段及异常所处的构造部位.更多还原

【Abstract】 Detecting earthquake precursors is a difficult topic of earthquake prediction at home and abroard.Carrying out rock deformation experiments in the laboratory and observing the evolution of the characteristics and the laws of the related physical parameters is fundamental and important to the exploring of earthquake precursors.In this study,a sample of compressive en echelon fault set was used to perform the deformation experiment.An infrared thermal image system recorded the temperature variations of the rock samples during the deformation stage.The deformation stage of precursory significance is divided into a strongly-deviation-from-linearity stage,meta-instability stage and instability stage based on the stress-time curve.The purpose of this article is to study the spatial and temporal variations of the thermal field in each stage especially the meta-instability stage and summarize the possible precursory phenomena.The experimental results show that: The temperature in the jog area increases because of compressive stress state during the strong-deviation-from-linear stage;the region of temperature increase moved to the faults from the jog area and the high temperature points on the faults spread and connect due to the converting of fault dislocation from local to overall during the stage of meta-instability,and synergy of temperature increase on the faults and synergy of temperature decrease in between the faults(including the jog area) are two important signals before the instability;The temperature of the whole sample decreases because of stress release except for increasing on the faults caused by friction during the instability stage.In short,there are evident characteristics of thermal field in the stage of meta-instability,which is helpful to identify the meta-instability state;the temperature varies in different deformation stages and different tectonic positions,which means the stage of the deformation and the tectonic position of anomaly should be taken into consideration when we are trying to find thermal anomaly related to the tectonic activity.更多还原